Tim Tebow and the Denver Broncos' offense have lost their mojo. They struggled mightily the past three weeks against the 3-4 defenses of the New England Patriots, Buffalo Bills and Kansas City Chiefs.

Now he faces the Pittsburgh Steelers, who have a much better version of the alignment with the league's top-ranked defense. Does Tebow have a chance for more unlikely magic? Or does he face Mile High odds to win a playoff game?

AFC Game of the Week

Pittsburgh Steelers at Denver Broncos, 4:30 p.m. Sunday. The Steelers like to be aggressive with their zone-blitz schemes under Dick LeBeau, but look for them to hold back a bit here. What has been working against Tebow is working to keep him in the pocket and locking up on his two outside receivers man-on-man. That leaves five to six defenders in the middle to stop the run and control shorter routes.

You can bet the Steelers will lean a lot on strong safety Troy Polamalu here. He will fill hard against the run, which the Broncos must do often. On the few occasions Denver will trust Tebow to drop back, Polamalu will be ready to either trick him into throwing an interception or fly upfield to limit his scrambling. This is a pretty bad matchup for Tebow, because when he tries to throw to his wide receivers, he'll see them struggle to gain separation against the Steelers' physical cornerbacks.

The Steelers will be without starting free safety Ryan Clark for this game and feature back Rashard Mendenhall in the playoffs. Mendenhall's loss because of a knee injury might be a factor down the line, but not here.

Detroit Lions at New Orleans Saints, 8 p.m. Saturday. This is one of two rematches from the regular season. The Saints beat the Lions 31-17 at home in prime time a month ago in Week 13. Since Dec. 4, quarterbacks Drew Brees and Matthew Stafford have gotten hotter.

Brees threw for 16 touchdowns and averaged 361 yards over the past four games, with a 126.4 passer rating. For Stafford, those numbers are 14, 378 and 113.6. So with those sizzling passers working to uncoverable targets Jimmy Graham and Calvin Johnson, expect more of a shootout—and a much closer game.

“I guess there’s some carryover from that game where you remember how the game unfolded, the type of talent that you were going up against, but then again a lot’s happened in the last four weeks," Brees said Tuesday. "I feel like we’re playing better football than we were then. I feel like they’re playing better football than they were then. Certainly they’re healthier."

The defenses here like to be aggressive, but they must hold back and commit seven and eight men to coverage.

The difference will be the running game. The Lions have tried to establish one with different backs while fighting injuries. The Saints, despite putting rookie first-rounder Mark Ingram on injured reserve, are in great shape between the tackles with Pierre Thomas and Chris Ivory. Look for guards Jahri Evans and Carl Nicks to control the middle against Ndamukong Suh and help wear down Detroit's front four—so Brees will feel less of a rush in the second half. Saints 38, Lions 29.

Upset of the Week

Atlanta Falcons over New York Giants, 1 p.m. Sunday. Congratulations to the Giants. They found their identity as a high-flying passing team with a red-hot Eli Manning. They also have an elite front-four pass rush with Osi Umeyniora, Justin Tuck and Jason Pierre-Paul.

But as good as the Giants looked against the Cowboys, the Falcons are steadier overall with a more reliable, balanced offense.

Matt Ryan, with receiving targets Roddy White, Julio Jones and Tony Gonzalez, will be comfortable throwing it around with Manning in windy MetLife Stadium. But unlike Manning, he can lean on a strong ground game with Michael Turner, who got going again last week. Turner's hard running can help keep Giants pass rushers from teeing off.

The Giants will have spectacular pass plays—probably from wideout Victor Cruz—but their league-worst rushing attack (89.2 yards per game, 3.5 yards per carry) will cost them. That's the one missing element from their Super Bowl XLII run, and that's why this playoff stint will be a lot shorter. Falcons 27, Giants 24.

First Game of the Week

Cincinnati Bengals at Houston Texans, 4:30 p.m. Saturday. Although this isn't a marquee matchup, the Texans will enjoy it. It's their first playoff game. Andre Johnson and Owen Daniels, who have been waiting for this moment for a long time, will make sure they enjoy it.

Andy Dalton is the better of the two rookie quarterbacks, but he'll be on the road against a tougher defense than the one T.J. Yates will see.

Just like the first meeting in Week 14—when a last-second Yates touchdown pass produced a 20-19 Texans victory at Cincinnati—Houston's defense will focus its coverage on go-to guy A.J. Green. That will allow the Texans' 3-4 pass rush, led by Connor Barwin, to fly into Dalton's face.

Dalton has a decent back to help him in Cedric Benson, but Yates has a much more dynamic and versatile one in Arian Foster. After getting much-needed rest in Week 17, Foster will be ready to explode as a runner and receiver. He'll be doing plenty of bows here as the Texans will get an encore in Baltimore for Round 2. Texans 23, Bengals 16.